1. Field of the Invention
The present invention relates to a method for preparing the working gas in a gas turbine installation in accordance with the preamble of claim 1. It also relates to the design of a pressure wave machine with integrated combustion at constant volume for carrying out this method.
2. Discussion of Background
As high-pressure compressor part of a gas turbine installation, EP-B1-0 212 181 has proposed a pressure wave machine in which the high-pressure gas is produced by self-ignition of a fuel which, for its part, is injected or blown into the cell rotor in the region of the low-pressure channels from fuel nozzles in a housing of the pressure wave machine. The self-ignition here takes place in the manner of detonation when the fuel/air mixture meets a compression wave occurring in the region of the introduction of the fuel. The consequently occurring pressure waves on the one hand produce high-pressure air in the corresponding regions of the rotor space, the said air being fed through a high-pressure air duct to a combustion chamber for the production of driving gas for the gas turbine.
On the other hand, as the cells of the rotor progress in the rotor space, the pressure waves produce an intermediate-pressure driving gas and a low-pressure driving gas in a further region of the rotor space, the said gases being fed via the intermediate-pressure gas duct and high-pressure air duct into the housing, to fuel-injection nozzles or into the housing on the combustion-chamber side, to the intermediate-pressure or the low-pressure part of the turbine.
Compared to a conventional gas turbine, a gas turbine with a pressure wave machine which serves as the high-pressure stage has important advantages which may be outlined as follows:
1. like a piston engine, the pressure wave machine permits very much higher gas temperatures;
2. the pressure wave machine allows combustion at a constant volume;
3. the pressure wave machine makes possible optimum use of transient processes (detonation transients).
While the traditional pressure wave machines, which are used as superchargers in internal combustion engines, utilize only the first effect, the pressure wave machine proposed in EP-B1-0 212 181 is based on a combination of all the effects listed above. However, with many fuels, for example with natural gas, the conditions striven for in the said patent as regards the pressure and temperature for igniting a detonation can only be achieved in extreme situations, which are however not typical of conventional machine construction, for which reason the fundamental potentials as regards advantages in efficiency of a pressure wave machine employed as high-pressure compressor part of a power plant are in practice not achieved with conventional machine construction.